Understanding ACL Determination Steps for Fisheries Management
Learn about the key parameters involved in maintaining sustainable fishing practices, such as Maximum Sustainable Yield (MSY), Optimum Yield (OY), Overfishing Limit (OFL), Allowable Biological Catch (ABC), and Annual Catch Limit (ACL). Discover how these values are determined and the actions required to prevent overfishing in fish stock. Follow the sequence and decision-making process for setting ACLs using a scalar approach for species like snappers in the US Caribbean region.
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Presentation Transcript
ACL DETERMINATION STEPS TO FOLLOW ACTIONS 2 AND 3
PARAMETERS MSY The largest long-term average catch or yield that can be taken from a stock or stock complex under prevailing ecological and environmental conditions. MSY proxy would equate to average catch. OY The amount of yield that provides the greatest overall benefit to the Nation, taking into account food production, recreational opportunities and the protection of marine ecosystems. OY Proxy and ACL would be equal values. OFL The maximum rate of fishing a stock can withstand (MFMT) or maximum yield a stock can produce (OFL), annually, while still providing MSY on a continuing basis. Defined as the amount of catch corresponding to the MSY proxy and overfishing would be determined to occur if annual catches exceed the OFL. ABC Is a level of a stock or stock complex s annual catch that accounts for the scientific uncertainty in the estimate of OFL. ACL The annual level to which catch is limited in order to prevent overfishing from occurring. Is the level of annual catch of a stock or stock complex that serves as the basis for invoking accountability measures.
How does one determine the actual How does one determine the actual values for the ACLs? values for the ACLs? MSY proxy would equate to average catch Overfishing Limit (OFL) OFL=MSY proxy Acceptable Biological Catch Annual Catch Limit OY proxy =ACL Catch (lbs) OY proxy=ACL=OFL*scalar Increasing ACL is the level of annual catch of a stock or stock complex that serves as the basis for invoking accountability measures.
Action 2 Example for snappers
CHOOSE THE YEAR SEQUENCE SNAPPERS PR STT STX Rec. ALT 1 97-01 94-02 94-02 00-01 ALT 2 99-05 00-05 99-05 00-05 ALT 3 99-07 00-07 99-07 00-07 ALT 4 03-07 03-07 03-07 03-07
CHOOSE SCALAR SNAPPERS No SCALAR 1.00 ALT 2(c) ALT 2(d) 0.85 ALT 2(e) 0.75 ALT 2(f) 0.50
SNAPPERS PR STT STX Rec. Action 2(a) ALT 2 99-05 00-05 99-05 00-05 Parameters for snappers in the US Caribbean Action 2(a), Alt 2, Alternative 2d MSY OFL OY/ACL (0.75 scalar) SNAPPERS 1,986,351 1,986,351 1,489,763
Action 3: Annual Catch Limit Allocation Action 3(a): Snappers: Aggregate or units? Snappers (USVI, PR) Snapper unit 1 (PR)
Average landings for the chosen years: SNAPPERS PR STT STX PR Rec. ALT 2 99-05 00-05 99-05 00-05 SNAPPERS 1,432,668 157,382 121,113 275,188 Snapper Unit 1 334,923 N/A N/A 105,344
Action 3: Annual Catch Limits Action 3(b): Commercial and Recreational Sectors? Action 3(b) Sector PR STT STX Commercial YES YES YES Recreational YES N/A N/A
Action 3: Annual Catch Limits Action 3(c): Geographical allocation Puerto Rico STT/STJ STX
ACL allocation for snappers and SU1 by Island sector and fishing sector 1999/2005 avg lbs 334,923 1,432,688 157,382 121,113 105,344 275,188 0.75 Average ACL vs 06-07 avg. scalar ACL Reduction 2006-2007 83,731 358,172 39,346 30,278 26,336 68,797 PR Com SU1 PR Com Snappers STT/STJ Snappers STX Snappers PR Rec SU1 PR Rec Snappers 0.75 0.75 1,074,516 0.75 118,037 0.75 0.75 0.75 206,391 251,192 151,300 764,843 166,231 130,581 195,145 266,947 99,892 309,673 -48,195 -39,746 -116,137 -60,556 90,835 79,008 TOTAL Snappers 1,986,371 1,489,778 1,328,601 161,177
